昆明地区流感病毒血凝素的蛋白质结构分析

Protein structure analysis of influenza virus hemagglutinin in Kunming

目的对从昆明地区分离10株流感病毒的血凝素(HA)基因进行蛋白质结构分析,与WHO推荐株进行比较,分析其异同。方法从流感病毒中提取RNA,进行RT-PCR扩增血凝素基因,对扩增产物测序进行蛋白质结构分析。结果蛋白质结构分析表明A/Kunming/01/2008(H1N1),A/Kunming/07/2008(H1N1)测出的序列大部分位于HA1,包括一小部分HA2和WHO 2007-2008年推荐株EU 100724.1对比,主要是第226位点不同,分别被Arg和Gln取代;A/Kunming/02/2008(H3N2)、A/Kunming/04/2008(H3N2)和WHO 2007-2008年推荐株CY034116.1相比,变异位点为154Asp→Asn,188Gln→His,218Val→Gly,248Asn→Asp,255Ile→Val,均位于蛋白表面,但对蛋白的结构没有产生大的影响;B/Kunming/10/2008和B/Kunming/09/2008有3点突变,分别为221Ala-Ile、281Arg-Gly、550Asp-Ile,但未引起蛋白质表面形状和电荷的变化;另外4株(两株H1N1和两株B型)与推荐株基本一致。结论两株A(H1N1)与推荐株EU 100724.1的抗原性基本一致,另外两株A(H1N1)与流行株代表株的同源性相对前两株要略低,HA基因已有位点发生突变;两株A(H3N2)与分离年代较近的全国流感病毒流行株代表株同源性较高,高氨基酸的突变只有一个,突变对蛋白的结构没有产生大的影响;4株B型毒株属于Victoria系和国外地区及近年国内流行株代表株同源性相对较低,存在地区差异和抗原性差异,有必要对毒株的变异加强监测。

OBJECTIVE The protein structures of hemagglutinin in ten strains of influenza virus isolated in Kunming were analyzed and compared with the strain recommended by WHO so as to find out the differences.METHODS The influenza virus RNA was extracted and the hemagglutinin gene was amplified by reverse transcription-polymerase chain（RT-PCR）.The PCR product was sequenced and the protein structure was analyzed.RESULTS The results of protein structure analysis demonstrated that the sequences of A/Kunming/01/2008（H1N1） and A/Kunming/07/2008（H1N1） were located mostly in HA1 and partly in HA2.Compared with EU 100724.1 recommended by WHO in 2007 to 2008,the major difference was that the 226th site was replaced by Arg and Gln respectively.Compared with WHO recommended strain CY034116.1,the mutation sites of A/Kunming/02/2008（H3N2） and A/Kunming/04/2008（H3N2） were 154 Asp →Asn,188 Gln→His,218 Val→Gly,248 Asn→Asp and 255 Ile→Val,all of which were located on the surface of the protein with no serious impact on the protein structure.The mutation sites of B/Kunming/10/2008 and B/Kunming/09/2008 were 221 Ala-Ile,281Arg-Gly and 550 Asp-Ile.These mutations did not result in change of the shape and charge of the protein.Other four strains including two H1N1 strains and two B strains were basically the same as the recommended strain.CONCLUSION The antigenicity of two A strains（H1N1） was almost the same as the recommended strain EU100724.1,while the homology of the other two A strains（H1N1） with epidemic strain was lower than the former two strains.These strains had mutation sites in HA gene.Two A strain（H3N2） had high homology with epidemic and representative influenza virus strain separated recently and had only one high amino acid mutation which had no impact on the protein structure.The four B strains were belong to Victoria strain and had relativelow homology with aboard and domestic epidemic and representative strains in recent years.There were regional and antigen differences.It is necessary to strengthen the monitoring of the stain variation.